Fwd: Why we need to check for local buffers in BufferIsExclusiveLocked and BufferIsDirty?

[Srinath Reddy]

On Sun, Jan 26, 2025 at 9:49 PM Tom Lane <t...@sss.pgh.pa.us> wrote:

> Srinath Reddy <srinath2...@gmail.com> writes:
> > as suggested did the changes and attached the patch for the same.
>
> Uh ... what in the world is the point of changing
> BufferIsExclusiveLocked's signature?
>
>
as suggested did not change the BufferIsExclusiveLocked's signature and
here's the patch for the same.

Regards,
Srinath Reddy Sadipiralla,
EDB: https://www.enterprisedb.com <http://www.enterprisedb.com/>

From 3d232e3f5d94acd0493dce1a51a3c8d51e49a1c8 Mon Sep 17 00:00:00 2001
From: Srinath Reddy Sadipiralla <srinath2133@gmail.com>
Date: Wed, 29 Jan 2025 07:04:18 +0530
Subject: [PATCH 1/1] 	Handle local buffer cases properly in  
 BufferIsExclusiveLocked and BufferIsDirty

---
 src/backend/storage/buffer/bufmgr.c | 21 ++++++++++++---------
 1 file changed, 12 insertions(+), 9 deletions(-)

diff --git a/src/backend/storage/buffer/bufmgr.c b/src/backend/storage/buffer/bufmgr.c
index 0d8849bf89..23c9edfb71 100644
--- a/src/backend/storage/buffer/bufmgr.c
+++ b/src/backend/storage/buffer/bufmgr.c
@@ -2463,7 +2463,8 @@ ExtendBufferedRelShared(BufferManagerRelation bmr,
 /*
  * BufferIsExclusiveLocked
  *
- *      Checks if buffer is exclusive-locked.
+ *      Checks if buffer is exclusive-locked,For local buffers we act as exclusive lock is always
+ * held,because we don't initialize content locks for local buffers.
  *
  * Buffer must be pinned.
  */
@@ -2472,20 +2473,22 @@ BufferIsExclusiveLocked(Buffer buffer)
 {
 	BufferDesc *bufHdr;
 
+	Assert(BufferIsPinned(buffer));
+
 	if (BufferIsLocal(buffer))
 	{
 		int			bufid = -buffer - 1;
 
 		bufHdr = GetLocalBufferDescriptor(bufid);
+		return true;
 	}
 	else
 	{
 		bufHdr = GetBufferDescriptor(buffer - 1);
-	}
-
-	Assert(BufferIsPinned(buffer));
-	return LWLockHeldByMeInMode(BufferDescriptorGetContentLock(bufHdr),
+		return LWLockHeldByMeInMode(BufferDescriptorGetContentLock(bufHdr),
 								LW_EXCLUSIVE);
+	}
+	
 }
 
 /*
@@ -2501,6 +2504,8 @@ BufferIsDirty(Buffer buffer)
 {
 	BufferDesc *bufHdr;
 
+	Assert(BufferIsPinned(buffer));
+
 	if (BufferIsLocal(buffer))
 	{
 		int			bufid = -buffer - 1;
@@ -2510,11 +2515,9 @@ BufferIsDirty(Buffer buffer)
 	else
 	{
 		bufHdr = GetBufferDescriptor(buffer - 1);
-	}
-
-	Assert(BufferIsPinned(buffer));
-	Assert(LWLockHeldByMeInMode(BufferDescriptorGetContentLock(bufHdr),
+		Assert(LWLockHeldByMeInMode(BufferDescriptorGetContentLock(bufHdr),
 								LW_EXCLUSIVE));
+	}
 
 	return pg_atomic_read_u32(&bufHdr->state) & BM_DIRTY;
 }
-- 
2.43.0